I would. Capela has collapsed against more talented opponents in the playoffs. Dieng can do what Capela does plus shoot the 3-ball and that has enormous advantages.
The even bigger coup here, of course, is Covington. A starting line-up of Harden, Russ, Covington, Tucker, and Dieng would be amazing. Gordon, Hartenstein , and whoever is hot from three coming off the bench seems like as a good a playoff rotation as we could hope for.
This trade hinges on the value of Capela. It would help if the guy second in the league in rebounds and a solid defender was getting even a bit of All-Star buzz. Maybe Minnesota can play Capela with KAT and sees that fit. If Minnesota does not care for Capela, hopefully a third-team would facilitate this. I would add a pick or two to make this happen if need be.